`scatstat2` documentation

The `scatstat2` function returns statistical values of all points within a given radius of each value. This is similar to taking a moving mean, but points do not need to be equally spaced.

See also `scatstat1`.

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## Contents

## Syntax

zbar = scatstat2(x,y,z,radius) zbar = scatstat2(x,y,z,radius,fun) ybar = scatstat1(...,options)

## Description

`zbar = scatstat2(x,y,z,radius)` returns the mean of all `z` values within specified radius at each point (x,y).

`zbar = scatstat2(x,y,z,radius,fun)` applies any function fun to `z` values, default `fun` is `@mean`, but it could be anything you want, even your own anonymous function.

`zbar = scatstat2(...,options)` allows any options that the function accepts. For example, 'omitnan'.

## Example: Local median

Consider this noisy data set of 5000 scattered points:

N = 5000; x = randi(750,N,1); y = randi(750,N,1); % z contains *real* structure, plus lots of noise: z = sind(x) + cosd(y) + 3*randn(size(x)); scatter(x,y,10,z,'filled') axis image title 'noisy scattered 2D data'

It almost looks like there's nothing there but noise. Filter out the high-frequency noise by taking the local median within a 75 unit radius:

z_median = scatstat2(x,y,z,75,@median); scatter(x,y,10,z_median,'filled') axis image title 'local median'

## Author info:

This function was written by Chad A. Greene of the University of Texas at Austin's Institute for Geophysics (UTIG), June 2016.